I don't know a fix for this, but I do know why it didn't work: Running gsettings as root doesn't work and that's how UCK or any other tool like this runs all the commands...
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Alin AndreiJun 28 '11 at 20:45

After check, shhac's answer did the trick for me (except i used 10_local-unity-launcher.gschema.override, but com.canonical.Unity.gschema.override will probably also work).
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LovinBuntuOct 3 '12 at 23:15